package com.xxl.job.admin.core.open.dingtalk;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.StringWriter;
import java.lang.reflect.Field;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Proxy.Type;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 网络工具类。
 */
public class WebUtils {
	private static final Logger		LOG						= LoggerFactory.getLogger(WebUtils.class);
	private static final String		DEFAULT_CHARSET			= "UTF-8";
	private static final String		METHOD_POST				= "POST";
	private static final String		METHOD_GET				= "GET";
	public static final String		APPLICATION_JSON_VALUE	= "application/json";

	private static SSLContext		ctx						= null;

	private static HostnameVerifier	verifier				= null;

	private static SSLSocketFactory	socketFactory			= null;

	private static int				keepAliveTimeout		= 0;

	/**
	 * 是否校验SSL服务端证书，默认为需要校验
	 */
	private static volatile boolean	needCheckServerTrusted	= true;

	/**
	 * 设置是否校验SSL服务端证书
	 *
	 * @param needCheckServerTrusted
	 *            true：需要校验（默认，推荐）；
	 *            <p>
	 *            false：不需要校验（仅当部署环境不便于进行服务端证书校验，且已有其他方式确保通信安全时，可以关闭SSL服务端证书校验功能）
	 */
	public static void setNeedCheckServerTrusted(boolean needCheckServerTrusted) {
		WebUtils.needCheckServerTrusted = needCheckServerTrusted;
	}

	/**
	 * 设置KeepAlive连接超时时间，一次HTTP请求完成后，底层TCP连接将尝试尽量保持该超时时间后才关闭，以便其他HTTP请求复用TCP连接
	 * <p>
	 * KeepAlive连接超时时间设置为0，表示使用默认的KeepAlive连接缓存时长（目前为5s）
	 * <p>
	 * 连接并非一定能保持指定的KeepAlive超时时长，比如服务端断开了连接
	 * <p>
	 * 注：该方法目前只在JDK8上测试有效
	 *
	 * @param timeout
	 *            KeepAlive超时时间，单位秒
	 */
	public static void setKeepAliveTimeout(int timeout) {
		if (timeout < 0 || timeout > 60) {
			throw new RuntimeException("keep-alive timeout value must be between 0 and 60.");
		}
		keepAliveTimeout = timeout;
	}

	private static class DefaultTrustManager implements X509TrustManager {
		public X509Certificate[] getAcceptedIssuers() {
			return null;
		}

		public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
		}

		public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
		}
	}

	static {

		try {
			ctx = SSLContext.getInstance("TLS");
			ctx.init(new KeyManager[0], new TrustManager[] { new DefaultTrustManager() }, new SecureRandom());

			ctx.getClientSessionContext().setSessionTimeout(15);
			ctx.getClientSessionContext().setSessionCacheSize(1000);

			socketFactory = ctx.getSocketFactory();
		} catch (Exception e) {

		}

		verifier = new HostnameVerifier() {
			public boolean verify(String hostname, SSLSession session) {
				return false; // 不允许URL的主机名和服务器的标识主机名不匹配的情况
			}
		};

	}

	private WebUtils() {
	}

	/**
	 * 执行HTTP POST请求，可使用代理proxy。
	 *
	 * @param url
	 *            请求地址
	 * @param params
	 *            请求参数
	 * @param charset
	 *            字符集，如UTF-8, GBK, GB2312
	 * @param connectTimeout
	 *            连接超时时间
	 * @param readTimeout
	 *            请求超时时间
	 * @param proxyHost
	 *            代理host，传null表示不使用代理
	 * @param proxyPort
	 *            代理端口，传0表示不使用代理
	 * @return 响应字符串
	 * @throws IOException
	 */
	public static String doPost(String url, Map<String, String> params, String charset, int connectTimeout,
			int readTimeout, String proxyHost, int proxyPort) throws IOException {
		String ctype = "application/x-www-form-urlencoded;charset=" + charset;
		String query = buildQuery(params, charset);
		byte[] content = {};
		if (query != null) {
			content = query.getBytes(charset);
		}
		return doPost(url, ctype, content, connectTimeout, readTimeout, proxyHost, proxyPort);
	}

	/**
	 * 执行HTTP POST JSON请求。
	 * 
	 * @param url
	 * @param content
	 * @return
	 * @throws IOException
	 */
	public static String doPostJSON(String url, byte[] content) throws IOException {
		return doPost(url, APPLICATION_JSON_VALUE, content, 6000, 10000, null, 0);
	}

	/**
	 * 执行HTTP POST请求。
	 *
	 * @param url
	 *            请求地址
	 * @param ctype
	 *            请求类型
	 * @param content
	 *            请求字节数组
	 * @param connectTimeout
	 *            连接超时时间
	 * @param readTimeout
	 *            请求超时时间
	 * @param proxyHost
	 *            代理host，传null表示不使用代理
	 * @param proxyPort
	 *            代理端口，传0表示不使用代理
	 * @return 响应字符串
	 * @throws IOException
	 */
	public static String doPost(String url, String ctype, byte[] content, int connectTimeout, int readTimeout,
			String proxyHost, int proxyPort) throws IOException {
		HttpURLConnection conn = null;
		OutputStream out = null;
		String rsp = null;
		try {
			try {
				conn = null;
				if (!StringUtils.isEmpty(proxyHost)) {
					conn = getConnection(new URL(url), METHOD_POST, ctype, proxyHost, proxyPort);
				} else {
					conn = getConnection(new URL(url), METHOD_POST, ctype);
				}
				conn.setConnectTimeout(connectTimeout);
				conn.setReadTimeout(readTimeout);
			} catch (IOException e) {
				LOG.error("request-error：url={},error={}", url, e.getMessage());
				throw e;
			}
			try {
				out = conn.getOutputStream();
				out.write(content);
				rsp = getResponseAsString(conn);
			} catch (IOException e) {
				LOG.error("request-error：url={},error={}", url, e.getMessage());
				throw e;
			}

		} finally {
			if (out != null) {
				out.close();
			}
			if (conn != null) {
				conn.disconnect();

			}
		}

		return rsp;
	}

	/**
	 * 执行HTTP GET请求。
	 *
	 * @param url
	 *            请求地址
	 * @param params
	 *            请求参数
	 * @return 响应字符串
	 * @throws IOException
	 */
	public static String doGet(String url, Map<String, String> params) throws IOException {
		return doGet(url, params, DEFAULT_CHARSET);
	}

	/**
	 * 执行HTTP GET请求。
	 *
	 * @param url
	 *            请求地址
	 * @param params
	 *            请求参数
	 * @param charset
	 *            字符集，如UTF-8, GBK, GB2312
	 * @return 响应字符串
	 * @throws IOException
	 */
	public static String doGet(String url, Map<String, String> params, String charset) throws IOException {
		HttpURLConnection conn = null;
		String rsp = null;

		try {
			String ctype = "application/x-www-form-urlencoded;charset=" + charset;
			String query = buildQuery(params, charset);
			try {
				conn = getConnection(buildGetUrl(url, query), METHOD_GET, ctype);
			} catch (IOException e) {
				LOG.error("request-error：url={},error={}", url, e.getMessage());
				throw e;
			}

			try {
				rsp = getResponseAsString(conn);
			} catch (IOException e) {
				LOG.error("request-error：url={},error={}", url, e.getMessage());
				throw e;
			}

		} finally {
			if (conn != null) {
				conn.disconnect();
			}
		}

		return rsp;
	}

	public static HttpURLConnection getConnection(URL url, String method, String ctype) throws IOException {
		return getConnection(url, method, ctype, null);
	}

	public static HttpURLConnection getConnection(URL url, String method, String ctype, String proxyHost, int proxyPort)
			throws IOException {
		Proxy proxy = new Proxy(Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));
		return getConnection(url, method, ctype, proxy);
	}

	private static HttpURLConnection getConnection(URL url, String method, String ctype, Proxy proxy)
			throws IOException {
		HttpURLConnection conn = null;
		if ("https".equals(url.getProtocol())) {
			HttpsURLConnection connHttps = null;
			if (proxy != null) {
				connHttps = (HttpsURLConnection) url.openConnection(proxy);
			} else {
				connHttps = (HttpsURLConnection) url.openConnection();
			}
			if (!needCheckServerTrusted) {
				// 设置不校验服务端证书的SSLContext
				connHttps.setSSLSocketFactory(socketFactory);
				connHttps.setHostnameVerifier(verifier);
			}
			conn = connHttps;
		} else {
			conn = null;
			if (proxy != null) {
				conn = (HttpURLConnection) url.openConnection(proxy);
			} else {
				conn = (HttpURLConnection) url.openConnection();
			}
		}

		conn.setRequestMethod(method);
		conn.setDoInput(true);
		conn.setDoOutput(true);
		conn.setRequestProperty("Accept", "text/plain,text/xml,text/javascript,text/html");
		conn.setRequestProperty("User-Agent", "aop-sdk-java");
		conn.setRequestProperty("Content-Type", ctype);
		return conn;
	}

	private static URL buildGetUrl(String strUrl, String query) throws IOException {
		URL url = new URL(strUrl);
		if (StringUtils.isEmpty(query)) {
			return url;
		}

		if (StringUtils.isEmpty(url.getQuery())) {
			if (strUrl.endsWith("?")) {
				strUrl = strUrl + query;
			} else {
				strUrl = strUrl + "?" + query;
			}
		} else {
			if (strUrl.endsWith("&")) {
				strUrl = strUrl + query;
			} else {
				strUrl = strUrl + "&" + query;
			}
		}

		return new URL(strUrl);
	}

	public static String buildQuery(Map<String, String> params, String charset) throws IOException {
		if (params == null || params.isEmpty()) {
			return null;
		}

		StringBuilder query = new StringBuilder();
		Set<Entry<String, String>> entries = params.entrySet();
		boolean hasParam = false;

		for (Entry<String, String> entry : entries) {
			String name = entry.getKey();
			String value = entry.getValue();
			// 忽略参数名或参数值为空的参数
			if (!StringUtils.isAnyBlank(name, value)) {
				if (hasParam) {
					query.append("&");
				} else {
					hasParam = true;
				}

				query.append(name).append("=").append(URLEncoder.encode(value, charset));
			}
		}

		return query.toString();
	}

	protected static String getResponseAsString(HttpURLConnection conn) throws IOException {
		String charset = getResponseCharset(conn.getContentType());

		// 此时设置KeepAlive超时所需数据结构才刚初始化完整，可以通过反射修改
		// 同时也不宜将修改时机再滞后，因为可能后续连接缓存类已经消费了默认的KeepAliveTimeout值，再修改已经无效
		setKeepAliveTimeout(conn);

		InputStream es = conn.getErrorStream();
		if (es == null) {
			return getStreamAsString(conn.getInputStream(), charset);
		} else {
			String msg = getStreamAsString(es, charset);
			if (StringUtils.isEmpty(msg)) {
				throw new IOException(conn.getResponseCode() + ":" + conn.getResponseMessage());
			} else {
				throw new IOException(msg);
			}
		}
	}

	private static String getStreamAsString(InputStream stream, String charset) throws IOException {
		try {
			BufferedReader reader = new BufferedReader(new InputStreamReader(stream, charset));
			StringWriter writer = new StringWriter();

			char[] chars = new char[256];
			int count = 0;
			while ((count = reader.read(chars)) > 0) {
				writer.write(chars, 0, count);
			}

			return writer.toString();
		} finally {
			if (stream != null) {
				stream.close();
			}
		}
	}

	private static String getResponseCharset(String ctype) {
		String charset = DEFAULT_CHARSET;

		if (!StringUtils.isEmpty(ctype)) {
			String[] params = ctype.split(";");
			for (String param : params) {
				param = param.trim();
				if (param.startsWith("charset")) {
					String[] pair = param.split("=", 2);
					if (pair.length == 2) {
						if (!StringUtils.isEmpty(pair[1])) {
							charset = pair[1].trim();
						}
					}
					break;
				}
			}
		}

		return charset;
	}

	/**
	 * 使用默认的UTF-8字符集反编码请求参数值。
	 *
	 * @param value
	 *            参数值
	 * @return 反编码后的参数值
	 */
	public static String decode(String value) {
		return decode(value, DEFAULT_CHARSET);
	}

	/**
	 * 使用默认的UTF-8字符集编码请求参数值。
	 *
	 * @param value
	 *            参数值
	 * @return 编码后的参数值
	 */
	public static String encode(String value) {
		return encode(value, DEFAULT_CHARSET);
	}

	/**
	 * 使用指定的字符集反编码请求参数值。
	 *
	 * @param value
	 *            参数值
	 * @param charset
	 *            字符集
	 * @return 反编码后的参数值
	 */
	public static String decode(String value, String charset) {
		String result = null;
		if (!StringUtils.isEmpty(value)) {
			try {
				result = URLDecoder.decode(value, charset);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
		return result;
	}

	/**
	 * 使用指定的字符集编码请求参数值。
	 *
	 * @param value
	 *            参数值
	 * @param charset
	 *            字符集
	 * @return 编码后的参数值
	 */
	public static String encode(String value, String charset) {
		String result = null;
		if (!StringUtils.isEmpty(value)) {
			try {
				result = URLEncoder.encode(value, charset);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
		return result;
	}

	public static Map<String, String> getParamsFromUrl(String url) {
		Map<String, String> map = null;
		if (url != null && url.indexOf('?') != -1) {
			map = splitUrlQuery(url.substring(url.indexOf('?') + 1));
		}
		if (map == null) {
			map = new HashMap<String, String>();
		}
		return map;
	}

	/**
	 * 从URL中提取所有的参数。
	 *
	 * @param query
	 *            URL地址
	 * @return 参数映射
	 */
	public static Map<String, String> splitUrlQuery(String query) {
		Map<String, String> result = new HashMap<String, String>();

		String[] pairs = query.split("&");
		if (pairs != null && pairs.length > 0) {
			for (String pair : pairs) {
				String[] param = pair.split("=", 2);
				if (param != null && param.length == 2) {
					result.put(param[0], param[1]);
				}
			}
		}

		return result;
	}

	public static String buildForm(String baseUrl, Map<String, String> parameters) {
		StringBuilder sb = new StringBuilder();
		sb.append("<form name=\"punchout_form\" method=\"post\" action=\"");
		sb.append(baseUrl);
		sb.append("\">\n");
		sb.append(buildHiddenFields(parameters));

		sb.append("<input type=\"submit\" value=\"立即支付\" style=\"display:none\" >\n");
		sb.append("</form>\n");
		sb.append("<script>document.forms[0].submit();</script>");
		String form = sb.toString();
		return form;
	}

	private static String buildHiddenFields(Map<String, String> parameters) {
		if (parameters == null || parameters.isEmpty()) {
			return "";
		}
		StringBuilder sb = new StringBuilder();
		Set<String> keys = parameters.keySet();
		for (String key : keys) {
			String value = parameters.get(key);
			// 除去参数中的空值
			if (key == null || value == null) {
				continue;
			}
			sb.append(buildHiddenField(key, value));
		}
		return sb.toString();
	}

	private static String buildHiddenField(String key, String value) {
		StringBuilder sb = new StringBuilder();
		sb.append("<input type=\"hidden\" name=\"");
		sb.append(key);

		sb.append("\" value=\"");
		// 转义双引号
		String a = value.replace("\"", "&quot;");
		sb.append(a).append("\">\n");
		return sb.toString();
	}

	/**
	 * 由于HttpUrlConnection不支持设置KeepAlive超时时间，该方法通过反射机制设置
	 *
	 * @param connection
	 *            需要设置KeepAlive的连接
	 */
	private static void setKeepAliveTimeout(HttpURLConnection connection) {
		if (keepAliveTimeout == 0) {
			return;
		}
		try {

			Field delegateHttpsUrlConnectionField = Class.forName("sun.net.www.protocol.https.HttpsURLConnectionImpl")
					.getDeclaredField("delegate");
			delegateHttpsUrlConnectionField.setAccessible(true);
			Object delegateHttpsUrlConnection = delegateHttpsUrlConnectionField.get(connection);

			Field httpClientField = Class.forName("sun.net.www.protocol.http.HttpURLConnection")
					.getDeclaredField("http");
			httpClientField.setAccessible(true);
			Object httpClient = httpClientField.get(delegateHttpsUrlConnection);

			Field keepAliveTimeoutField = Class.forName("sun.net.www.http.HttpClient")
					.getDeclaredField("keepAliveTimeout");
			keepAliveTimeoutField.setAccessible(true);
			keepAliveTimeoutField.setInt(httpClient, keepAliveTimeout);
		} catch (Throwable ignored) {
			// 设置KeepAlive超时只是一种优化辅助手段，设置失败不应阻塞主链路，设置失败不应影响功能
		}
	}
}
